Driver alerting device

ABSTRACT

A driver alerting device includes a transceiver adapted for mounting at the rearward end of a vehicle for directing its wave output rearwardly of the vehicle. Return wave signals for many objects within the transceiver range are picked up and supplied to the transceiver by an antenna. Any resultant doppler shift signal is amplified for driving an audio alarm adapted for placement within the passenger compartment of the vehicle. The circuit is adapted for electrical connection to the back-up light circuit of the vehicle for activation only when the vehicle transmission is engaged in reverse gear.

This application is a continuation of application Ser. No. 579,160,filed Feb. 10, 1984, now abandoned.

BACKGROUND OF THE INVENTION

The present invention is directed generally to a device for alerting thedriver of a rearwardly moving vehicle to the presence of any object inclose range behind the vehicle. More particularly, the present inventionis directed to a micro-wave radar device using the doppler shiftprinciple to detect the presence of a moving target within thetransceiver range.

Drivers of motor vehicles have always had a certain degree of difficultywith backing up their vehicles. Whereas this is due partly to thedifferent steering response of a rearwardly moving vehicle, mostbacking-up accidents are due to the driver's limited visibility. Manytrucks have a considerable blind spot directly rearwardly of the vehiclewhich is not visible through side mounted mirrors. But even in smallertrucks and passenger cars with rear windows, there may be blind spots atthe rearward corners of the vehicle and below the driver's line ofsight.

Devices have previously been known for detecting the presence of objectsbehind a vehicle but such devices have not achieved widespread usage.Devices which provide an audible alarm directed rearwardly of thevehicle are ineffective if a child, for example, in the path of thevehicle does not react to the alarm and if the vehicle driver does nothear the alarm. Certainly an external alarm will not remove stationaryobjects from the path of the vehicle.

Accordingly, an object of the invention is to provide an improved devicefor alerting the driver of a rearwardly moving vehicle to the presenceof a person or object within a short range distance behind the vehicle.

Another object is to provide such a device with a remote audible alarmsuitable for placement within the passenger compartment of a vehicle.

Another object is to provide such a device which employs micro-waveradar technology.

Another object is to provide a driver alerting device which may beeasily electrically and mechanically connected to a vehicle.

Finally, an object is to provide a driver alerting device which iseconomical to manufacture, simple and rugged in construction andefficient in operation.

SUMMARY OF THE INVENTION

The driver alerting device o the present invention includes atransceiver adapted for mounting at the rearward end of a vehicle fordirecting its wave output rearwardly of the vehicle. Return wave signalsfrom any object within the short transceiver range behind the vehicleare supplied to the transceiver through an antenna connection. Anyresultant doppler shift signal is amplified for driving the audio alarm.The circuit of the device is adapted for electrical connection to theback-up light circuit of a vehicle for activation only when the vehicletransmission is engaged in reverse gear.

The driver alerting device thus immediately sounds an alarm when anymoving or stationary object is detected within the short transceiverrange behind a rearwardly moving vehicle on which it is installed. Evenwhen the vehicle is stationary, but with the back-up lights activated,the device will signal the presence of any moving object within thetransceiver range. Because the device operates by micro-wave radar, itis unaffected by noise, light, or weather conditions such as snow, rain,heat and cold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic top plan view of the driver alerting deviceinstalled on a vehicle;

FIG. 2 is an electrical schematic circuit diagram of the driver alertingdevice; and

FIG. 3 is a perspective view of the transceiver housing of the device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The driver alerting device of the present invention is indicatedgenerally at 10 in FIG. 1 installed on the rear bumper 12 of a truck 14having a passenger compartment 16 situated forwardly of box 18. Device10 operates by micro-wave radar using the doppler shift principle todetect the presence of a moving target within the transceiver range.

The operating elements of the device 10 are wholly electronic and areshown in FIG. 2 as including a transceiver 20, an antenna 22, anintermediate frequency amplifier 24 and an audio alarm 26.

The transceiver 20 includes a gun diode 28 mounted in a wave guidecavity which acts as the transmitter and local oscillator, together witha schottky barrier mixer diode 30 for the receiver. Electromagneticradiation transmitted from the gunn diode 28 is reflected back at theantenna by any object within the transceiver range. If that object ismoving relative to the vehicle, the frequency shift of the wavereflected by the moving object is measured electronically and triggersactivation of the alarm 26.

In the preferred embodiment, output frequency of the transceiver 20 isfactory preset at 10.525 GIGA HERTZ. Power output is 5 milliwattsminimum. Operating voltage is 8 volts D.C. The resultant dopplerfrequency obtained is 31.39 HERTZ for each mile per hour of radiovelocity. The transceiver is unaffected by the presence of magneticfields, noise, light and varying weather conditions.

Antenna 22 may be provided as either a high gain antenna or low gainantenna. The high gain antenna is preferred for application with 1/4ton, 1/2 ton and 1 ton vehicles measuring 80 inches maximum in width.The low gain antenna is preferred on 1 ton and larger vehicles measuring80 inches and greater in width. The range of the antennas is adjustableand my be user set to accommodate virtually any vehicle. This adjustmentis incorporated in the intermediate frequency amplifier 24 and isaccessible from the outside of the unit. Antenna 22 is preferablyconstructed of machined aluminum and is also preferably flange-mounteddirectly to the transceiver 20, thus eliminating the effects of noiseand spurious response. Lines 32 in FIG. 1 illustrate an example of atypically adjusted wave pattern.

The intermediate frequency amplifier 24 is a solid state, multi-stageoperational amplifier designed to amplify and shape the resultantdoppler shift signal. The circuitry is card mounted and has built-inrange and sensitivity controls. The amplifier is designed to interfacewith the existing reverse switch 34 (FIG. 2) in order to activate thecircuit only during reverse operation of the vehicle. Reverse switch 34is typically associated with the vehicle transmission and isincorporated into the back-up light circuit of the vehicle forilluminating the back-up lights whenever the vehicle transmission isengaged in reverse gear.

The audio alarm 26 is mounted interiorly of the passenger compartment 16so as to be readily audible to the driver of the vehicle. Amplifier 24drives both the audio alarm 26 and a light emitting diode mounted on theunit. The purpose of the light emitting diode is to aid in theadjustment of the unit in the event that the alarm is not audible to theone adjusting the unit at the rearward end of the vehicle.

The transceiver 20 is shown in FIG. 3 as including a housing 36 which isdiagonally sectioned to provide a pivotal top cover 38. The wave outputfrom the transceiver 20 is transmitted outwardly through a rearwardlyprotruding channel section 40 on the rear wall of housing 36. A mountingflange 42 extends downwardly from the housing for ready attachment to avehicle bumper or the like.

The circuitry is card mounted and all components ar treated with aconformal coating to prevent the effects of moisture and salt.Electrical hook-up to the vehicle is achieved via a splash-proof fourcircuit connector mounted on the side of the unit. One of the four leadsis connected to the vehicle ignition switch, one to the back-up lightsor reverse switch 34 on the transmission, one to ground 44 and one tothe alarm 26.

The audio alarm is preferably a solid state piezoelectric alarm capableof developing 80 decibels at 12 volts D.C.

In operation, the transceiver 20 is activated to transmitelectromagnetic radiation whenever the vehicle ignition is on and thetransmission is engaged in reverse gear. This closes the vehicle reverseswitch 34 for illuminating the vehicle backup lights. A reducer may beprovided between the transceiver 20 and reverse switch 34 to adjust theoperating voltage to 8 volts D.C. The transceiver range spans the widthof the vehicle 14 and extends rearwardly approximately 6 to 12 feet. Themaximum range would be approximately 20 feet.

As the vehicle is driven rearwardly, reflected signals from any objectwithin the transceiver range, such as loading dock 46, are picked up byantenna 22 and supplied to the mixer diode 30 where the frequency shiftis measured electronically. Amplifier 24 is designed to amplify andshape the resultant doppler shift signal and to activate the alarm 26.Note that when the vehicle is backing up, both stationary and movingobjects within the transceiver range will be detected since there willbe relative movement between the transceiver and these objects. Evenwhen the vehicle is stationary, a moving object, such as a runningchild, will be detected by the transceiver and result in activation ofthe alarm. A stationary object will not be detected when the vehicle isstationary since there is no relative movement to cause a doppler shiftsignal to be generated. Thus the alarm will stop once the moving objectleaves the transceiver range. Likewise, when the buzzer is activated bya stationary object, it will stop once the vehicle is stopped.

Thus there has been shown and described a driver alerting device for avehicle which accomplishes at least all of the stated objects.

I claim:
 1. A driver alerting device for a vehicle having a back-uplight circuit reverse switch, comprising, a transceiver comprising amicro-wave radar device using the doppler shift principle to detect thepresent of a target within the transceiver range,means for supportingsaid transceiver at the rearward end of a vehicle for directing the waveoutput thereof rearwardly of the vehicle, means for supplying to saidtransceiver return wave signals from any target within the transceiverrange, an intermediate frequency amplifier operatively connected to saidtransceiver, said amplifier being operative to amplify and shape saidreturn wave signals, a remote indicator adapted for placement within oradjacent the passenger compartment of a vehicle, means for electricallyconnecting said remote indicator to said transceiver for activation ofsaid indicator in response to detection by said transceiver of returnwave signals from any target within the transceiver range, and means forelectrically connecting said transceiver to the back-up light circuitreverse switch of a vehicle for activation of said transceiver inresponse to activation of said back-up light circuit reverse switch of avehicle, said device being substantially unaffected, in operation, byvarying weather conditions.
 2. The driver alerting device of claim 1wherein said transceiver includes a wave guide cavity and a gunn diodemounted in said waveguide cavity for transmitting wave output therefrom.3. The driver alerting device of claim 2 wherein said transceiverfurther includes a schottky barrier mixer diode which is operative asthe receiver thereof.
 4. The driver alerting device of claim 1 whereinsaid means for supplying return wave signals to said transceivercomprises a high gain antenna.
 5. The driver alerting device of claim 1wherein said means for supplying return wave signals to said transceivercomprises a low gain antenna.
 6. The driver alerting device of claim 1wherein said means for supplying return wave signals to said transceivercomprises an antenna mounted directly to the transceiver.
 7. The driveralerting device of claim 1 wherein said intermediate frequency amplifieris a solid state multi-stage operational amplifier.
 8. The driveralerting device of claim 1 wherein said remote indicator comprises asolid state piezoelectric alarm.
 9. In combination, a vehicle havingforward and rearward ends, a passenger compartment, and a back-up lightcircuit reverse switch, a driver alerting device, comprisingatransceiver comprising a micro-wave radar device using the doppler shiftprinciple to detect the presence of a target within the transceiverrange, means for supporting said transceiver on the rearward end of saidvehicle for directing the wave output of the transceiver rearwardly ofthe vehicle, antenna means for supplying to the transceiver return wavesignals from any target within the transceiver range, an indicator,means for mounting said indicator in the passenger compartment of thevehicle, means for electrically connecting said indicator to saidtransceiver for activation of said indicator in response to detection bysaid transceiver of return wave signals from any target within thetransceiver range, said means for electrically connecting said indicatorto said transceiver including an intermediate frequency amplifieroperative to amplify and shape the output signal of said transceiver,and, means for electrically connecting said transceiver to the back-uplight circuit reverse switch of the vehicle for activation of saidtransceiver in response to activation of said back-up light circuitreverse switch of the vehicle, said device being substantiallyunaffected, in operation, by varying weather conditions.
 10. A driveralerting device for a vehicle having a transmission with a reverse gear,comprising, a transceiver comprising a micro-wave radar device using theDoppler shift principle to detect the presence of a target within thetransceiver range,means for supporting said transceiver at the rearwardend of a vehicle for directing the wave output thereof rearwardly of thevehicle, means for supplying to said transceiver return wave signalsfrom any target within said transceiver range, an intermediate frequencyamplifier operatively connected to said transceiver, said amplifierbeing operative to amplify and shape said return wave signals, a remoteindicator adapted for placement within or adjacent the passengercompartment of a vehicle, means for electrically connecting said remoteindicator to said transceiver for activation of said indicator inresponse to detection by said transceiver of return wave signals fromany target within the transceiver range, and means for activating saidtransceiver in response to actuation of said transmission to saidreverse gear, said device being substantially unaffected, in operation,by varying weather conditions.